Electrical circuit tester



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ELECTRICAL CIRCUIT TESTER Filed May 25, 1946 /C'l 6. f W] 5 V ATTE RN EYB Patented May 30, 1950 UNITED STATES PATENT OFFICE ELECTRICAL CIRCUIT TESTER Willis E. Show, Johnstown, Pa.

Application May 23, 1946, Serial No. 671,697

1 Claim. 1

This invention relates to a circuit tester and more particularly to a device which is used for testing wiring of an airplane, motor vehicle, or other apparatus wherein wires are used for carrying current and are liable to become broken and interrupt operation of the apparatus.

One object of the invention is to provide a tester so constructed that a clip carried by an insulated wire may be applied to a ground and a pointed stem then pressed against a live wire to be tested so that the sharp end of the stem will penetrate insulation of the wire and cause an electric bulb of the tester to be lighted.

Another object of the invention is to provide a tester having a handle resembling the grip of a pistol and carrying the bulb and the ground wire and also the pointed stern or feeler in such position that when the handle is held in a persons hand the ground wire will project rearwardly therefrom and the stem project forwardly from the handle in position to be applied to a wire to be tested.

Another object of the invention is to provide a tester wherein the stem has rearwardly extending forms or arms which support a mirror in front of the bulb and have their rear portions embedded in the handle and so shaped that the socket for the bulb is mounted between them and iirmly supported.

Another object of the invention is to provide a tester having a handle resembling a pistol grip and provided at its butt end with a pocket wherein sockets are mounted to carry extra bulbs.

Another object of the invention is to provide a tester which is of simple construction and very easy to operate.

The invention is illustrated in the accompanying drawings wherein:

Figure 1 is a view showing the improved tester in side elevation with portions in section;

Figure 2 is a front view of the tester;

Figure 3 is a sectional View taken along the line 3--3 of Figure 1.

The improved circuit tester has a handle I which is formed of hard plastic or other suitable insulating material and so shaped that it resembles the grip of a pistol. The upper end portion of the handle extends forwardly 'and is formed with a recess 2 which tapers rearwardly. A socket 3 for holding a bulb Il is embedded in the handle with its open front end communieating with the inner or rear end of the recess 2 and in the socket is a terminal plate 5 pressed forwardly by a spring I5 so that when the bulb is tted into the socket the center contact I of the bulb will be firmly engaged by the contact 8 of the plate. An insulated wire 9 extends from the socket 3 through a passageway I0 formed through the handle and this wire, which may be of any length desired, extends rearwardly from the handle and at its free end carries a clip II for gripping a metal object serving as a ground during testing a circuit.

A stem I2 formed of brass or other conductive material and tapered at its front end to form a sharp point I3 has its rear portion provided with forks or arms I4 which diverge rearwardly for a, portion of their length and are then bent to extend parallel to each other, rear ends of the arms being bent and curved inwardly towards each other, as shown at I5, and then forwardly to form fingers I 6 which are 'brazed to upper and lower portions of the socket 3. Since the socket is brazed to the fingers IB and the handle is molded about the socket and the rear portions of the arms a very firm connection will be established between the handle and the pointer and when the handle is grasped the pointer or stem will project forwardly from the handle. A pocket IT is formed at the butt end of the handle and in this pocket or recess are mounted sockets I 8 for carrying extra bulbs 4' which may be duplicates of the bulb 4 or bulbs of larger capacity. The bulb 4 may be a 6 volt bulb for testing a circuit of a motor vehicle, one of the bulbs 4 12 volts for testing construction equipment, and the other bulb 4' 32 volts for testing aircraft circuits, but it will be understood that bulbs of any desired voltage may be provided and selectively used.

When the tester is in use the clip I I is applied to a suitable ground and the handle I then grasped and the sharp front end of the stem I2 pressed against a wire to be tested. As the sharp end of the stem penetrates the insulation of the wire being tested contact will be made with the wire and if no break is in the wire up to the point contacted the bulb will be illuminated and since a reector mirror I9 is mounted between the arms I4 in front of the bulb the workman will instantly see the light. The stem may be applied to the suspected wire at various points until contact of the pointed end of the stem with the wire fails to cause the bulb to be lighted and a break in the wire thus easily located. Batteries and other electrical equipment may also be tested in a like manner in order to determine whether they are in proper working order.

Having thus described the invention, what is claimed is:

In a circuit tester, a handle formed of molded insulating material and including a lower portion constituting a grip, and an upper portion arranged angularly with respect to said lower portion and provided with a recess in its front end, said recess having its front portion tapered, there being a straight passageway in said upper portion arranged in the same plane ,as said recess and communicatingwith the latter; a bulb'- holding socket snugly seated in the rear portion of said recess, a central terminal arrangedV in said socket, an insulated Wire extending from the terminal in said socket through said passageway, a clip secured to the free end oi'saidl Wire, a stem of conductive material provided With a sharp point on its front end for penetrate ing insulation of a wire to be tested, a pair of'1 in spaced, parallel.V ngers, saidv ngers beingr embedded in said handle, said ngers being arranged in contact With opposite sides of said socket and secured thereto, and a mirror arranged forwardly of the bulb-holding socket and extending between the diverging portions of said arms and secured thereto.

WILLIS E. SHOW.

REFERENCES CITED Theffollowing references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,395,819 Guy Nov. 1, 1921 1,415,254 Martzen May 9, 1922 1,454,623 Carter May 8, 1923 1,471,625 Opsahl Oct. 23, 1923 1,639,889 Humm Aug. 23, 1927 2,229,927 Kamper Jan. 28, 1941 FOREIGN PATENTS Number Country Date 647,226 France July 24, 1928, 

